SLITRK1 and Tourette syndrome: For example, Slitrk1 has been postulated to be causative for Tourette syndrome (Abelson et al., 2005; Grados and Walkup, 2006), although subsequent studies (Keen-Kim and Freimer, 2006; Chou et al., 2007; Fabbrini et al., 2007; Scharf et al., 2008) have questioned the validity of conclusions reached by these earlier studies (Keen-Kim and Freimer, 2006; Chou et al., 2007; Fabbrini et al., 2007; Scharf et al., 2008).